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Determining the current load on a shared server by a given site
Graphs are available allowing you to monitor all sites as a whole on the server in question. You may also refer to any MySQL slow logs and Apache error logs.
Log into your control panel
Click on Statistics -> Real time monitoring
By using client-side tools such as the Web developer menu in Firefox or Google Webmaster, you can get quite a detailed breakdown of the loading time of your pages and hence identify those which may be causing excessive load.
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